Rotary pump machine



Feb 14, 1933. E. EYSTQN 1,897,190

ROTARY PUMP MACHINE Filed April 21, 1931 6 Sheets-Sheet l 6 6 IIIIIIII,

vFeb- 1933- G. E. T. EYSTON ROTARY PUMP MACHINE 6 Sheets$heet 2 Filed April 21, 19:51

Feb. 14, 1933. E EYSTQN 1,897,190

ROTARY PUMP MACHINE Filed April 21, 1931 e Sheets-Sheet 4 .F.6. cal w 57 Fb. 14, 1933. G E T, EYSTON 1,897,190

ROTARY PUMP MACHINE Filed April 21, 1931 e Sheets-Sheet 5 llllllllll Feb. 14, 1933. G. EYSTON 1,897,190

ROTARY PUMP MACHI NE Filed April 21, 1931 6 Sheets-Sheet 6 Patented Feb. 14, 1933 UNITED STATES PATENT OFFICE GEORGE EDWARD THOMAS EYSTON, OF LONDON, ENGLAND, ASSIGNOR TO POWER'PLUS (1927) LIMITED, OF LONDON, ENGLAND, A

CORPORATION OF GREAT BRITAIN ROTARY PUMP MACHINE Application filed April 21, 1931, Serial No. 531,763, and in Great Britain April 22, 1930.

This invention comprises improvements in and connected with rotary pump and like machines of the kind comprising a piston body mounted within an outer rotary cylinder or working chamber and adapted, while revolving with the latter, to partake of a reciprocatory motion back and forth across the space of the cylinder or in the working chamber.

The object of the invention is to obtain more efiicient control of the working parts in machines of this nature and particularly to obtain improved drive and to take up centrifugal efiects on the piston with minimum of friction so that the piston parts may be of robust construction.

According to this invention, the piston body is placed under control of parts having rolling contact engagement with each other, the piston rolling bodily with one ofthese parts, and drive of the piston is effected by rotating one of the rolling contact part-s about its own axis. The rolling contact parts may comprise a circular gear surface which is mounted rotatably in the machine and a centric circular gear surface on the piston, the diameters of these surfaces being so related that on rotating the first one it may, by engagement with the circular gear surface of the piston, positively reciprocate the latter in the outer cylinder or working chamber. If desired, both the piston and the outer rotary cylinder or working chamber may have drive applied to them so that reactionary pressure between the piston and the sides of the working or pumping space is reduced or elimi-' nated. In this way improved operation of the machine is obtained and smoother working of the piston ensues, greatly reducing friction.

For the purpose of enabling the invention to be readily understood, reference is directed to the accompanying drawings in which:

Figures 1, 2 and 8 are cross-sections of a rotary pump machine construction according to these improvements, with the piston and cylinder shown in successive rotatory positions.

Figure at is a longitudinal section of a modified construction.

Figure 5 is a cross-section on the line VV of Figure 4. I

Figure 6 is a longitudinal section illustrating another modification.

Figure 7 is a cross-section on VIIVII of Figure 6, and

Figure -8 shows another modification in longitudinal section.

The machines illustrated in the drawings are of the same general nature as those described in the specification accompanying m patent application Serial No. 463,113, filed June 23, 1930, in that they comprise a rolling contact form of control for the reciprocatory piston.

In Figures 1 to '3, 0 is the outer casing of the machine, I; a revoluble cylinder or drum mounted to revolve in the outer casing, and (l the pumping space or working chamber of the machine formed in the cylinder 7). The working chamber is bounded on two sides by flats e for travel of a piston a to and fro and 72 are ports at the ends of the chamber, which co-operate with fluid-inlet and delivery connections Z, m of the outer casing. The flats or the piston tips may be fitted with spring pressed packing pads or strips to maintain a seal. The rolling contact control of the piston is efl'ected by the circular gear f mounted eccentrically in the casing 0 and an internal gear surface 9 on the piston, and as the machine rotates the surface 9 rolls cycloidally with the piston round the gear 7 in a manner similar to that described and illustrated in the specification of my said patent application. In the drawings of such patent application, the member 7 was shown normally stationary but according to the present case, in Figures 1 to 3, this member f is mounted rotatably in the casing 0 and is formed as a toothed gear adapted to be r0 tated about its own centre. Thus, in revolving, the gear 7 is adapted to reciprocate the piston through the internal gear 9 and the piston in turn may rotate the cylinder 7) owing to its engagement with the flats e. The surfaces 7 and 9 may be geared together the line of thegears' f and g, Ifthe-relativediame- 7 eccentricity ofthe gear f with respect to the central axis'of the machine. There is a relation betweenithe speedsof the gear f and.

i by toothed formations or. otherwise to'produce the drive and whether the teeth extend along the'whole'length or only part of the length of these parts, it will be clear that there willbea cycloidal roll of the surface 9 about thesurfaee fas is shown by. theiprogressive position'ofthese parts in Figures 1 to the dot-and-dash pitch linesindicate toothed surfaces f and g in Figures 2 and In the operation ofithe machine, at' higher'speed's' the centrifugaliforce is operative on the piston to maintain its reciprocator'y movements under controlofzthe co-acting surfaces f, g;

.and any tendency of the piston to slip and. fall out of position when thefmachine comes to",

' rest or at starting, may bje-prevented in suitable manner, as by the provision shown in Figures Sand Z -wherein the parts 1, 2,,ef-

" fectively prevent slip and fall of the piston and also eliminate possibility of dead-centre mrsto'ppages w ,t j

s In order to obtaintherolling contact .effeet in Figures 1:to 3 it is iessentialftohave appropriate relation between the diameters 1,1the gear, is, would have to be stationary in order to obtain the rolling contactrelation between these parts andtlie machine would i i have to be driven by rotating'the drum 6' or the piston ofIny patent application afore- 7 said) in Figures 1 to 3, therefore, wherein drive of the piston is to be'eiiected by groi tating the gear f, the diameter ratio must f begreater or less'than 2:1.f Thediamet'er ofthe gear is therefore made larger or smaller than half the diameter of the internal gear g. It is "show-n'larger the drawings and by "rotatingthe gear 7, rolling contact engagement between the same and the gearjg can i be achieved with efiective operation of the piston and rotation ofthe cylinder 6, the

1 speed of the cylinder 1) equals w centre ofthe piston'moving round the dotted circle 00 of which the radius-is equal to the the cylinder 6 as followsre-lf r be the radius of the pitch circle of thegteethof the gear 7, and r. theradius of the dotted circle m, then the ratio ofthe speed ofj such gear tothe is greater than rand;

if 7-l .-i s les'sthan 1"; The radius'ot the pitch circle of the internal gear gis' equal to the sum jof rand-r. Itis to be'noted that there is, of course; a rotarymovementtogether of V the gears f, g', but there is: no slip so that the relative movementbetween them is 1 purely a rolling contact engagement. The radii of the gears f, g would of course, be selected to suit the particular speed ratio desired but it willbe obvious-from the'above formulaethat if r is made rgreaterthan' 1", the speed of revolutionofthegear g and thus of the oylinder will be greater than the speed of the gear 7. Ifrbe less than 1", rolling contact will be maintained with the gear f rotating in the opposite direction to'the cylinderti'and gear 'gi the speeds being equal to each other or a frac'tion ora' multiple one of the other depending on the relative Values of 1' and 1*.

By wayof example; assume that the valve,

r bee qual to 1 and the angular'speed of the corresponding speeds for the gearnf have the v l a 1 4 Angular v speedpt gear in l Radius (1') of gear r m'inches i- Reverse rotation r If 5* eqil alle 'dj 92' t pe 6f. the get;

cylinderbelrequiredtobe 1000 revolutions permin-ute, then example of pitch radii and would jbe 0, thus demonstrating thatsthe aforesaid, 2:1 diameter ratio s between the gear-g and the gear frequires the latter to be stationary as" described. 'Forforwardrotation of'the-gear fequal speeds of the cylinder and gear can only correspond with, an r infinity value for r but with reverse rotation Y of the gear f, equal speeds are obtained with speed increases indefinitely.

Theoretically, the diameter ratio between the gear 9 and the gear fmay be any. value greater or less than 2: 1 but in practice, 60111-5 siderations of mechanical efficiency of the drive and lubrication would make the ratio.

2 of speeds between the gears best when of the order of approximately 10 1. V I In Figures l and 5, the construction is'of similar nature but there is a-vplurality; of

pistons a, a, aFwhich are cylindricaland thecylinder '6 also is driven by gearing 0' from the shaft f fof the severalgea rs f of the'respective pistons. In some cases aicylindrical ofthe cylinder is of much advantage, because itrelieves the piston of reactionary pressure V v I 1' equaltog- *For lower values of 7" the piston structure is advantageous because it is easy to construct and an ndependent dr ve at the flats e and thus reduces friction. It is seen in Figures land 5 that the gears f are formed on members f keyed on the shaft f but this is only to facilitate assembly because three pistons a, a, 0. are used. If there were a smaller number of pistons, the gears 7 could be formed on the shaft f The machine is shown in Figures 4 and 5 with the three pistons a, a, a spaced apart angularly for balancing purposes. The middle piston a would be made twice as long as each of the others a, a so as to be heavy enough to balance the latter. The working chambers such as d for all the pistons are provided in the same cylinder 6 which is mounted in ball bearings 37 in the end covers 1'. The pistons, as before, have a rolling contact control, Figures at and 5 show, however, that the gears f, g, need only extend for part of the length of the parts f and a, a, a so that the rolling contact engagement is partly over toothed surfaces, and partly over plain surfaces marked f 9 These plain surfaces 7, g would be equal in diameter to the pitch circles of the gears f, g and thus they enable the centrifugal pressure to be taken by the shaft f to the relief of the teeth of the gears. Floating crescent-shaped bushes or rollers may be inserted in the crescent space between the plain surfaces f 9 in the manner described in my patent application aforesaid, so as to eliminate slip should this tend to occur at low speeds, thereby relieving the teeth of lateral stresses. The teeth of the gears f, g and the gearing may be constructed so that they do not come out of mesh in the event of the machine being used in the vertical position or when stationary under the action of gravity. There might, of course, be separate revoluble cylinders for each of the pistons in Figures 4 and and separate gearings like the gearing 0 be provided for driving each of these cylinders. This separate cylinder idea may also be used in other constructions comprising a plurality of pistons and the separate cylinders would be freely mounted in cases where no direct drive by gearing such as 0 were used.

According to Figures 6 and 7 piston control is effected by rolling contact engagement of a surface on the piston with a stationary surface in the casing and piston drive is effected from the corresponding rotary cylinder. There are two pistons a, a side by side and two rotary cylinders 6, Z) and the working chambers are separated by a central transverse partition t in the outer casing c. The pistons are lenticular but may be of other forms, and each has a plane circular surface 9 adapted to have rolling contact engagement with the circular surface of an internal stub f fixed to the partition if of the casing, the diameter ratios of the two surfaces being 2 1 respectively. The rotary cylinders b, b are mounted by shaft parts 2 in spaced anti-friction bearings u in the end covers of the casing and have internally projecting axial parts 1) with gears w, adapted to engage with gears w of the same diameter on the ends of a gear shaft 3 ez'tending centrally through the cam parts f of the two pistons. Drive is applied to the shaft of one of the rotary cylinders 12, b and this effects drive of the other through the gear shaft 3 but separate drive may be applied to each side of the machine if de sired. The pistons have gear surfaces 9 at the outer ends and these mesh with the external gears 00 on the gear shaft y, the gear ratio being, say 3:1. in this machine, the gears 09 on the. shaft 3 are of less diameter than (c. g. half the diameter of) the stubs f so that the pistons a, a revolve in reverse direction to such gears. The latter, however, are geared to tl e rotary cylinders through the gears to so that actually the latter and the pistons revolve in the same direction. The gear surfaces roll cycloidally round the gears w in a similar manner to which the surfaces g roll round the stubs f as will be readily understood but, at the same time, the gears 20, 00 effect positive drive of the pistons. In order to prevent the pistons from slipping and from dropping under the action of gravity when the machine is stationary, the central partition is fitted with eccentric parts 1 engaged with parallel surfaces 2 of the pistons. Lubrication of the gears and appurtenant rotary parts is effected in simple manner by ducts 3 in the central partition t and the gear shaft y.

The modification shown by Figure 8 comprises a single cylinder Z) and built-up piston a of cylindrical or lenticular form, but instead of external gears for driving the gear shaft y as in Figures 6 and 7 the external gear to on the axial projection '0 of the rotary cylinder meshes with a double gear on the gear shaft 1 one side of this double gear being internally toothed as at 4 to engage the gear to and the other side being externally toothed as at 5 to engage the internal gear 9* of the piston. The stub f is fixed in one end cove: of the machine and the cylinder b is mounted by a shaft .2 in spaced anti-friction bearings u in the other end cover, and the first mentioned end cover has an eccentric part 1 engaging parallel surfaces 2 of the piston as before to prevent the latter from slipping and from falling out of position when the machine comes to rest. The cylinder gear 10 drives the double gear forwardly in this case and therefore the external gear part 5 of the double gear is made greater in diameter than the stub f Means other than the eccentric part 1 on the end cover or partition of the casing may be adopted in this and the other modifications for preventing fall of the piston or pistons when stationary, such as a floating crescent-shaped ",said surfaces being adapted to have rolling bushor roller as describediin connectionzwith Figures 4 and5. v I

I (3l2iII1: A V f 1. Rotary pump or like machine comprise ing'an outer casing, a rotary working chamber in said casing, a piston operative in said working chamber, a circular surface on the;

piston and a circular surface mounted eccentrical'ly insaid casing, said surfacesbeing adapted tohave rolling contact engagement with each other to control movement of the piston in said workingchamber, an axial driveshaft for sa dirotary work mg chamberand: a gear drive between said" shaft and said piston.

' 2. Rotary pump or likemachine comprising an outer casing, a rotary cylinder, mounted in: said casing and formed with a transverse working chamber, a piston operative in saidworking chamber, an internally circular surface on. the piston vand a cooperative externally circular surface mounted eccentrically and stationar ly 1n sald casing,

contact engagement with each other to control movement of said piston in said working "chamber, a drive shaft fixed to saidcylinder,

a gear shaft mount ed co-axially with said externally circular surface, a gear drive between said shafts and an internal'gear drive 7 between the gearshaft and saidpistoni 3; A rotary p'ump or like machine compris ing a revoluble working chamber, a piston adapted to reciprocate in? and 'revolve with said chamber, a'curved gear surface disposed on an d-non-rotatably fiXQClWltll respect to said piston, a companion curved gear surface disposed in the machine andiengaged in continuous cycloidallyrolling fashion by said gear surface of'said pistonas the latter] revolves with said'w'orking chamber, and means for imparting rotation to said piston through said, gear surfaces.

' 4. A rotary pump orlike machine compris-v ing a revoluble working chamber, a piston adapted to reciprocate m andjrevolvewlth said chamber, a circular gear surfacedlsposed on and-non-rotatably fixed with respect to said piston, a second'clrcular gear surface disposed revolubly in the machine and engaged in continuous cycloidally rolling fashion bysaidgearsurface of said'pistonas the latter revolves with said working'chamber,

and means fornrotating said'second circular gear surface to efiect rotation of said 131513011.

5. A rotarypump or like machine comprising a revoluble working chamber, a piston adapted to reciprocate in and revolve with said chamber, an internally circulargear *suro face disposed on and non rotatably fixed with respect to said piston, an gexternallycircular gear surfaceanounted'in the machine and engaged in continuouscycloidally rolling fashion bysaid internally circular gear surface-of the piston as the latter revolves with effect rotation of saidip iston-.

' ing a "revol'uble workingchamber, a piston adapted to reoiprocate in said-chamber-as the slow speeds'or at startin said working' ch'amber and means for rotatingsaid externally circular gear surface to 6; Arotarypumpor like machine comprislatter rev0lves,,a plain circular surface and a toothedcircularsurface disposed on and non-rotatably fixed with re'spectto said piston,aplaincircular surface and a toothed circularsurfa-cdisposed in the casing ofthe machine, and engaged incycloidally rolling fashionfwith the first-mentioned surfaces as a the piston revolves with said working "chamber,' and means for imparting rotation; tosaid piston through said toothed surfacea V 7. A rotary pump or like machine in-ac A cordance with claim 6, in which the plain circular surface in the casing of themachine is a non-rotatablyifixed surface.

8. Arotarypump or like machine comprising a, revol-uble Workingc ha'niber, a piston adapted-to reciprocate m and revolvewith saidchamber, a circular gear surface disposed on and non-rotatably fixd with respect to saidpiston, a companion circular gear surface disposed eccentrically in the machine and engaged in continuous cycloidally rolling fashion by'said circular gear' surface of said piston as the latter revolves with said work'- ing'chamber, means for imparting rotation to said piston andworking chamber through said fge'ar surfaces and additional'means for driving said revoluble working chamber.

' 9. Afrotary-pum'p or like machine compris-, ing an outer casing, a cylinderywith a trans-'- verse working space, mounted torevolve in said casing, alpiston mountedto reciprocate der, an internal gear, surface of circular contour formed centrically within" and nonrotatably fixedfwith respect to 'said' piston, a revolublex ci'r'c'ular gear surface disposed eccentricallyin ysaidcasing and engaged in continuous cycloidally rolling contact by said circular gear surface of said piston as the latter revolves with said cylinderand means forimparting rotationto said piston through said gear surfaces.

10. A rotary pump or like machinecom iprismg a revoluble'working chamber, 'a p1svolves with said workingchamber, means for imparting rotation to saidpiston through said gear surfaces and means operative to prevent said piston from falling and thereby prevent possible dead-centre stoppages GEORGE rnwina 'rnouis izrsrou."

.in said space from side to side of said'cylin- 

